Robots carry out tasks with speed, accuracy, and repeatability that can not be matched by manual techniques. They are used in a variety of applications, from welding to picking up and handling all sorts of items. In order to carry out these tasks, robots are equipped with "end effectors," devices designed to effect a desired action. End effectors often take the form of mechanical fingers, claws, or jaws that mechanically compress articles between two members. While these types of end effectors (sometimes called "grippers") are effective for use in industrial environments and to manipulate objects that are hard and relatively heavy, they are not useful for handling lighter, delicate, or easily crushed items.
For example, plastic glasses and cups are difficult to handle using typical robot grippers because they are usually made from materials that can be crushed or broken relatively easily. In addition, cups and glasses are often placed inside one another to create hard-to-handle, large stacks. The stacks can be unstable if they are not grasped along their entire length. It is also difficult to remove and place stacks of items in boxes and similar containers, because the area within such containers is limited and stacks are often surrounded on three sides (either by another stack or a wall of the container). This makes it difficult to grab or grip the stack without damaging the container or other stacks. Another problem with most grippers is that a minimum clearance from items in the operating environment must be provided so that they can properly open and close. Typically, an end effector requires more operating space when its jaws are opened. This makes it difficult to handle items in tight spaces such as occurs when packing or unpacking cups or similar items. Thus, these tasks are often done using manual or semiautomated mechanisms. However, if an end effector existed that could grasp stacks of such items and deliver such items without damage, in the confines of a container, the benefits of robotic automation could be realized.